Process for producing hydrocarbons



ne 1944' F. E. FREY EIAL i Q ,3

PROCESS FOR PRODUCING HYDROCARBONS Original Filed Oct. 19, 1936 INVENTOR FREDERICK E. FREY HARDLD J. HEPP Patented June 6, 1944 UNITED, STATES PATENT OFFICE PROCESS FOR PRODUCING HYDROCARBONS Frederick E. Frey and Harold J. Hepp,'Bartle|- ville, Okla, assignors to Phillips Petroleum Company, a corporation of Delaware Original application October 19. 1936, SerialNo. 106,482. Divided and this application April 27, 1940, Serial No. 332,089

8 Claims.

olefin and paraffin hydrocarbons to produce especially valuable motor fuels and paraffin hydrocarbons of branched structure.

This application is a division of our co-pending application, Serial No. 106,482, filed October 19, 1936, entitled Process for producing hydr'os carbons," now U. 8. Patent 2,209,450, granted July 30, 1940,

An object of this invention is to produce a liquid motor fuel essentially paraffinic in nature without resorting to olefinie polymer formation and the subsequent hydrogenation of the olefin hydrocarbons.

Another object of this invention is the use of a synthetic conversion stock composed of hydrocarbons of simple and controlled composition to produce a liquid motor fuel havina especially desirable characteristics and controlled properties, reflecting the identity of the reactant hydroearbons selected.

A further object is the production of individual paraffin hydrocarbons of purity and identity not attainable from natural products nor as the result of usual operations for hydrocarbon manufacture.

Another object is the production of various branched paraiflns of a single species or a mixture of simple composition within a wide range of boiling points or volatilities. 4 I

Still another object is the production of valuable paraffinic chemical raw materials, such as neopentane (2,2-dimethylpropane) and neohexane (2.2-dimethylbutane) which may be chlorinated to yield predominantly the relatively non-corrosive primary chlorides.

Further objects of our invention will become apparent as the following discussion proceeds.

A number of methods have been proposed for the production ofhigher molecular weight hydrocarbons from normally gaseous hydrocarbons such as are found in the residue cases from natural gasoline plants or the distillation and cracking of petroleum.

(Cl. mill-683.4)

fuel are produced. Polymerization of oleflns directly into larger molecules is thus efl'ected, while parafilns so treated are thermally split into smaller molecules, part of which are oleflns, which concurrently polymerize. It has alsobeen proposed to decompose parafiins thermally into oleflns-at a low reaction pressure, thereby favoring the efficient production of simple oleflns,

It has been proposed to convert hydrocarbon asses, consist n'z essentially of paraffins hirzhcr than methane, erco'nsisting of olefins or their mixtures such as arenroduced by the foregoing methods, by heat and pressure into hydrocarbons of higher molecular weight. By such means normally liquid hydrocarbons suitable for motor which may subsequently be polymerized by a heat and pressure conversion step. Under particularly drastic temperature conditions, the oleflnic, parafllnic and heterocyclic polymers are decomposed and normally liquid hydrocarbons of simple composition, but of aromatic structure. survive by reason of the heat stable character of aromatic hydrocarbons. The milder conversion temperatures which lead to aliphatic liquid hy-, drocarbons yield products rich in olefins, and sometimes parafiins, but of exceedingly complex composition, this partly by reason of the high velocity of concomitant secondary reactions.

Such normally liquid hydrocarbon fuels are ordinarily suitable for use as motor fuel in internal combustion engines but diillculties arise from their use under the exacting conditions encountered in certain types of engines such as the high compression type used in aircraft. Thus olefinic and aromatic fuels often lead to excessive heating and variable performance with modification in engine design. Moreover, use of unsaturated hydrocarbons in motor fuels may lead to deterioration of antidetonation qualities during storage as well as formation of gum, which causes deposits in fuel. systems and on valves. Fuels composed of p'araiflnic hydrocarbons possess characteristics such that these difficulties do not arise. It is well known that parafllns of branched structures possess excellent antidetonating characteristics and comparative freedom from heating tendencies in high compression engines. Parafilns of normal structure, on the other hand, have strong detonating characteristics and are accordingly undesirable. Furthermore, for best performance and safety in use, stringent requirements have been applied in respect to volatility and distillation range for fuels intended for such use. Certain branched paramns having suitable volatility characteristics can be obtained from uncracked natural gas gasoline and petroleum distillates by a highly specialized fractional distillation but the relative amount of such hydrocarbons is ordinarily not large. some structurally possible and valuable species are absent, and undesirable parafllns sometimes overlap the more valuable in distilling temperatures. This leads to considerable expense in producing in this way branched paraffins meeting both antidetonating and volatility requirements. The production of certain suitable antidetonating paraillns by involved synthetic means has been proposed, For example: 2,2,4-

from isobutylene, which lends itself to catalytic polymerization into diisobutyiene, which is then hydrogenated to produce this octane.

In copending applications hereafter to be re.- ferred to there have been described methods for producing motor fuel hydrocarbons predominating in branched paraiiins by reacting together olefins and parafllns under heat and pressure with suitable control of olefin concentration during reaction.

Thus in U. S. Patent 2,002,394 issued to Frederick E. Frey on May 21, 1935, covering a Process for converting hydrocarbons it was proposed to add at a plurality of points olefins to a parafiinic hydrocarbon stream under the influence of elevated temperature and pressure to produce a motor fuel predominating in branched paraflins. In the copending application, Serial Number 12.981, filed March 25, 1936, by Frederick E. Frey relating to a Process for converting hydrocarbons, now U. S. Patent 2,104,296, granted January 4, 1938, there is proposed a process wherein the exothermic heat of reaction between olefins and parafiinic material assists in controlling the reaction temperature level. Also in the copending application Serial Number 82,954 filed June 1, 1936, by Frederick E. Frey relating to a Process for converting hydrocarbons, now U. S. Patent 2,270,700, granted January 20, 1942. there is described a process for manufacturing motor fuel from raw hydrocarbons deficient in olefin content.

We have discovered that under suitable conditions of conducting the conversion operation the simple juncture of parai'iins with olefins can be effected, with limited extent of secondary and concomitant reactions, to yield a product of simple molecular composition consisting essentially of such resulting juncture compounds of parailinic type. and this is a part of our invention. We have discovered that under such conditions the identity of the parafilns produced reflects the identity of the reactant parafilns and olefins, the thermal conversion being of the nature of a controlled chemical synthesis. It is a part of our invention to react together selected single species of paraillns and olefins or simple mixtures to produce at will individual parafilns and simple mixtures of various desired structures and varying boiling points and molecular weights. It is possible to apply fractional distillation economically to such' products to procure desired paraifins in a pure or concentrated state.

According to the present invention a parafiln hydrocarbon in its pure state is maintained at a pressurei .'oi'z 1,000 to 10,000 pounds or more per square.inch;and is at the same time maintained at a reaction temperature such that decomposirange described, the olefin is maintained dispersed in the parafiin in a low concentration, less than loweight per cent. The juncture of paraillnwith olefin takes place essentially according to the equation trimethylpentane. an octane, has been prepared unaccompanied by extensive juncture of olefin with olefin by reason of the low concentration of olefin present. The reaction is then interrupted and the parafiins thus formed are separated from the products. An olefin in concentration of less than 10 per cent may be initially introduced into the parafi'in and the heating conducted in any conventional manner, such as by passage through a heated tube coil to produce a limited yield of synthetic parafiins. If it is desired to react over 10 per cent of total olefin,

introduction of olefin is made to the reacting mixture during the course of the reaction as olefin is consumed. the addition being made in such a manner that the concentration of unreacted olefin in the reacting mixture is maintained at a desired low level. This may be accomplished by introducing olefin at a plurality of points distributed along a tube coil through which the reacting mixture flows, or an. olefin rich paraffin-olefin mixture may be injected into a reaction chamber in which an essentially paramnic mixture is dispersed and mixed with the reacting mixture while the latter is circulated in the reaction chamber so as to flow the partially reacted mixture repeatedly past the point of dishigh pressure while a low concentration of olefin is maintained, ranging from 1 to 5 per cent, for example, at 4,000 pounds pressure per square inch. Pressures of 2,000 to 3,000 pounds per square inch and'more are preferable. At a pressure as low as 1,000 pounds parafilns are synthesized in somewhat less purity but the products are predominantly the juncture compounds of the olefin and paramn reacted if their production is limited to less than 10 per cent of the total reactants per thermal treatment with correspondingly low olefin content, which in such a case may be below 10 per cent, and better if below 5 per cent. Ethylene undergoes somewhat more eiilcient juncture with parafllns than do the higher olefins under such low pressure conditions. As higher concentrations of parafilns are built up the thermodynamic limit for the reaction is approached and the synthetic parafiins undergo decomposition. yielding a product which while rich in isoparafllns, acquires a very complex composition. High conversion pressures permit increased formation of desirable products,

which may amount to per cent of the reaction mixture at 5,000 to 10,000 pounds per square inch, before other products outweigh the parafilns resulting from primary juncture of reactant parafilns and olefins. Olefins other than ethylene require somewhat higher pressures under otherwise equivalent conditions. The extent of conversion which permits the ready purification of desired paraflins from the paraifinic products by fractional distillation is dependent on the materials involved and can be readily determined by trial. By the partial conversion of the reactant by weight for reaction periods which may range from about 1 to about 30 minutes,the most suit paranins will be understood the limitation of extent of conversion in accordance with the foregoing description.

The temperature and reaction time should be 'such as will effect the conversion with only a small extent of splitting reactions. The conditions are readily determined by trial and typical conditions are set forth in the examples to be presented.

,All paraflin hydrocarbons undergo reaction with olefins, for example the juncture of ethylene taking place most readily with the replacement of tertiary hydrogen by ethyl, less readily in replacing secondary hydrogen, and, least readily' I in replacing primary hydrogen. Methane and ethane react at a somewhat slower rate than the higher paraflins under equivalent conditions. Olefins of varying structure and molecular weight undergo reaction with paramns, the higher reac tion pressures, or low extent of conversion per thermal treatment being usually required with increasing number of alkyl substituents attached to the ethylene molecule, if a product rich in primary olefin-paraflin juncture products is desired.

While reactant paraflins and. olefins consisting each of asingle molecular species are particularly desirable to yield paraflln products of simple composition, it is sometimes desirable to use simple mixtures to obtain a desired result. Thus, ethylene and isobutane react to produce hexanes, but a required or specified motor fuel of somewhat lower volatility and gradually rising distillation curve may be produced by reacting both ethylene and propylene with the isobutane whereby heptanes together with hexanes, both of high branched structure, may be produced to meet a distillation curve specification of this kind. The olefins may be introduced at separate points or may be mixed prior to the introduction. For economic reasons it is sometimes preferable to use simple mixtures, thus ethylene produced by pyrolysis to serve as a reactant may be associated with more or less of difflcultly reacting ethane when absorption or distillation is used to separate the ethylene from other pyrolysis products. Similarly 2,2-dimethylbutane and 2 -methylpentane, both hexanes, may be reacted together with ethylene to produce a mixture of octanes, which are complex and highly branched, but meeting for motor fuel blending purposes specific volatility and anti-detonating requirements.

,The drawing diagrammatically shows one type of apparatus for realizing and effecting the teachings of this invention.

The process of our invention may be conducted in an apparatus such as is shown in the drawing, which is a diagrammatic side elevation of elements, not drawn to scale, and illustrates one means b which the process may be practiced.

able exact conditions being determined by trial.

While under these conditions there is admixed with the parailln hydrocarbon, in a manner to be hereinafter described, a small amount of an] olefin hydrocarbon, the concentration of the saidolefin unreacted at any part of the reaction zone will be maintained atless than 10 pe1- cent by weight of the total hydrocarbons present, and the total amount of olefin introduced, per unit amount of paraflin present, will be such that, except at particularly high pressure, not more than 30 per cent by weight of th eflluents from the reaction will consist of synthesized hydrocarbons of higher molecular weight.

The desired low concentration of olefin in the reaction zone may be accomplished in a number of different ways. An olefin hydrocarbon, either in a pure state or somewhat, diluted by the material introduced through pipe i0, is introduced through pipe l5 and is compressed by pump ii to a suitable pressure and carried by conduit I! to the conduits designated by the reference numerals I8 to 26 inclusive, in which the flow is controlled by'valves designated by the reference numerals 21 to 35 inclusive, respectively; Another olefin hydrocarbon, also either in a pure state or somewhat diluted by the material introduced through pipe it, may be introduced, as will be discussed later, through pipe 36 and compressed by pump 31 to a suitable pressure and carried by conduit 38 to the conduits designated by the reference numerals 39 to 43 inclusive, in which the flow is controlled by the valves designated by the reference numerals 44 to 48 inclusive, respectively, and which conduits lead to the conduits l9, I9, 20, 2| and 22 respectively. Hydrogen may be in troduced as will be discussed, through pipe 49, and compressed by pump 50 to a suitable pressure, and passed through the conduit 5| to conduits 52, 53 and 54. The hydrogen is passed through these conduits and is controlled by valves 55, 56 and 51 respectively, and passed to conduits 39, 40 and ll respectively and thence on through conduits I8, I9

Referring now to the drawing, an essentially pure parafiinic hydrocarbon is introduced through pipe l0 and compressed toa suitable working or reac tion pressure by pump II. This pressure will be between 1,000 and 10,000 or more pounds per square inch. Having been brought to this pressure the parafiinic material passes through conduit l2 and is subjected to a reaction temperature in coil l3, suitably housed in a furnace or heating means l4. Such a reaction temperature will be between 750 and 1100 F., and will be such that the total thermal decomposition of the parafiin hydrocarbon treated, due .to its exposure to said temperature, will be less than 5 percent and 20 respectively and thence into the reaction coil [3.

In one mode of operation the valves 44 to 48 inclusive, and the valves 55, 56 and 51 are closed, and valves 21 to 35 inclusive are so controlled that a limited quantity of the olefin, introduced through pipe l5, passes to the reaction through each of them, the total amount of unreacted olefin at any one point not exceeding 10 per cent by weight of the hydrocarbon present at that point. With such a procedure effluents from the reaction coil l3 will pass through conduit 58 and valves 59 and 60 to the separating means 6| with valve 62 in conduit 63 and the valve 64 in conduit 65, which conduits make connection with the insulated reaction chamber 66, being closed as will be the valve 61in conduit 88. The pressure in separating means 6|, which will be somewhat lower than the reaction pressure, is controlled by the valve 50.

Another mode of operation, inolving the addition of two olefins separately to the reacting stream, may also be followed. In this procedure; a paraflin hydrocarbon is introduced through line I0, compressed to a suitable pressure in excess of 1,000 pounds per square inch by pump II and passed through conduit I! to the reaction col] ill, where it is subjected to a reaction temperature bon, either in a pure state, or diluted as discussed previously, is introduced through pipe l5, compressed to a suitable pressure by pump l6 and led by means of conduit I! to the stream of paraflln hydrocarbons, being introduced through conduits 23, 24, Hand 26, valves 21 to 3| inclusively being closed. The flow of this olefin into the mixture through pipes 23, 24, 25 and 26 is controlled by valves 32, 33, 34 and 35 respectivehr. Another olefin, either in a pure state or somewhat diluted by the material introduced through pipe I, is introduced through pipe 36, compressed to a suitable pressure by pump 31 and passed through conduit 38 and into the reacting mixture through conduits 39 to 43 inclusive and conduits l8 to 22 inclusive, valves 21 to 3| inclusive being closed as mentioned, and valves 55, 56 and 51 also being closed; The fiow of this second olefin stream is controlled by valves 44 to 48 inclusive respectively. In such a mode of operation the paraflin hydrocarbon introduced through pipe I is reacted first with one olefin to form a higher molecular weight paraflin hydrocarbon as a product and then with another olefin to form a similar higher molecular weight par'aflin hydrocarbon as a product which, however, contains a different number of carbon atoms per molecule than does the first mentioned product. Efiluents of the reaction coil l3 pass directly to the separator 6| as heretofore described.

I-Iigher molecular weight hydrocarbon material produced in this manner is predominantly composed of relatively few species of parafflnjc hydrocarbon molecules, most of which have amore or less highly branched structure. A certain limited amount of olefinic material usually polymerizes with itself, forming a limited amount of higher molecular weight clefins. Although heavier hydrocarbon material recovered asa final product is essentially parafiinic in nature, it may be desirable further to decrease any olefinic molecular species. We have found that hydrogen intrcduced into the last part of the reactioncoll, after paraflin-olefin polymerization reactions have been essentially completed, will react with olefin present, to form the corresponding 52, valves 56 and in conduits 53 and 54 being a closed. The fiow of hydrogen through the conduit 52 is controlled by valve 55, and continues through conduit 39 into conduit l8 and into the mixture, reacting with the olefins present in the mixture in the very last part of the coil I3. The total eflluents of the coil I3 are passed to separator 6| as has been described.

In another mode of operation the olefin may be introduced only through conduit I! to conduit l6 and through valve 21, while the remaining valves 28 to 35 inclusive, 44 to 48 inclusive and 55, 56 and 51 are closed. In such a case, the eflluents may be introduced turbulently into insulated reaction chamber 66, which is efiected by valve 59 being closed and valve 62 in conduit 63 and valve 64 in conduit 65 being open, Coil l3 serves in this case to impart heat sufiicient to sustain reaction in chamber 66 but not prematurely to react the olefin-rich mixture in coil l3 when olefin concentration employed therein exceeds the desired low reaction concentration.

All the eflluents from the reaction may pass "directly into separating means 6|, or valve 61 in conduit 66 may be partially opened and only a certain portion of the eilluents allowed to pass into separating means 6| through valve 60, the remaining eflluents'passing through valve 61 and conduit 68 to the hot oil pump 66 which forces the stream through conduit Ill and valve H and into the conduit l2.

The introduction of small amounts of pure olefin material into the reaction to maintain the' various conditions desired may be made by any one of these methods or any obvious modifications of them, and any past or future references to such introduction of olefins will be so understood. Olefinic hydrocarbons so introduced may be diluted before introduction into the reaction zone with some of the paraffinic reactant, as discussed, so as to inhibit polymerization of the olefin with itself at the point of introduction when such olefins are introduced into the reacthrough pipes l5 and 36 will be appreciably greater than its respective concentration in the reaction mixture as discussed previously, and the amount of Daraflln hydrocarbon thus introduced with the olefin is to be considered when considering the composition of the mixture at any point.

The olefin concentration is purposely kept low, so as to favor reactions involving paraffin-olefin juncture and to inhibit polymerization of one olefin species with itself or with another species. Because of the high concentration of parafflnic material throughout the reaction coil, more than one olefin species may be introduced for reaction, such introduction being made separately, without going outside the scope of this invention. The composition of the higher boiling material thus synthesized will still be simple, and will consist predominantly of only a few molecular species. Some higher molecular weight olefinic hydrocarbons may be formed as a side reaction from polymerization of the olefins introduced. When such olefins are present, hydrogen may be added as has been discussed, to produce a more completely parafiinic product. If such olefins are present in a very low concentration, such as 2 per cent by,weight or less, hydrogen in not too great an excess may be added at only one point as shown above. With somewhat larger amounts of olefins present, two or more points of hydrogen addition may be desirable as provided for in the operation. In such a case, hydrogen added at any but the last point should be in such a quantity as to be insufficient for reaction with all the olefin at the point of introduction. In this manner excessive development of heat and reactions involving splitting of parafiinic molecules will be inhibited. When reaction chamber 66 is used, addition of hydrogen will not be desirable.

In separating means 6| hydrocarbons of high molecular weight will be removed and discharged through conduit 12 to the separating means 13, wherein any heavier products are separated and 'discharged through conduit 14 and valve 15. Hy-

drocarbon materials of motor fuel boiling range, consisting predominantly of a limited number of molecular species, and essentially parafllnic in 1 nature, will pass from separator I3 through conduit 16 to fractionating means 11, wherein isoparaflln fractions concentrated as to desired components are separated and discharged through -conduits .18, I9, 80 and 8! which are controlled by the valves 82, 83, and 85 respectively. The products may then receive any further desired purification treatment The eflluents of the reaction passing into separator BI and not being discharged therefrom by conduit,

The following examples will further illustrate the novelty and advantages of this invention:

' 4 Example I Referring to an apparatus whose essential characteristics may be illustrated by reference to the drawing, propane of better than 99 per cent purity was introduced through conduit l0 and increased to 4,500 poundsper square inch pressure by pump II and led through conduit 12 to a reaction coil 13 where it was subjected to a reaction temperature of 950 F. A seven to one recycle ratio was used by proper manipulation of valves 60 and 61, the recycle going through conduit 68 to pump 69 and conduit 10 to conduit l2. A small amount of ethylene of greater than 99 per cent purity was added through conduit l5, pump l6, conduits l1 and 26 and valve 35, no other points of addition being used. The length of the reaction coil 13 and the rate of flow through it was such that the average exposure of the propane to the reaction temperature was about 4.1 minutes, while maintaining a steady concentration oireactingethylene of 2 per cent, The effluents of the process passing to the separator 6| contained 11.2 per cent by weight of gasoline hydrocarbons, with unreacted material in such proportion that by appropriate recycling of this unreacted material an ultimate yield of 90 per cent by weight of gasoline was possible. In 100 parts by weight of hydrocarbons charged there were 8.9 parts of ethylene and 91.1 parts of propane. The gasoline boiling fraction had the following composition by weight:

Per cent Cal-I10 2.6 ISO-C W 55.5 n-C5H12 16.4 Cal-I12 2.0 CsH14 7.3 C7H14 1 .8 C'1H1s 10.1 Cs+ 4.3

Iso-pentane, which has high antidetonating qualities and which constitutes a valuable ingredient of aviation fuels, was present in the pentane fraction to the extent of '17 per cent by weight, or 55.5 per cent of the total gasoline produced, and was isolated in a pure state by fractional distillation.

. Example 11 A procedure. essentially-identical to that given in Example I was followed,using as reactants pure isobutane as the paraflln and pure ethylene as the olefin. In 100 parts by weight of the hydrocarbons charged there were 12.1 parts of ethylene, and 87.9 parts of isobutane. A pressure of 4,500 pounds per square inch was used and a reaction temperature of 940 F. with a-total exposure time of about 4 minutes. The products contained 16.1 per cent by weight of gasoline boiling hydrocarbons, with a possible ultimate yield by proper recycling of 89 per cent. The gasoline boiling fraction hadthe following composition by weight:

Per cent Pentenes 5.0 Isopentane 3.3 n-Pentane 4.9 Hexenes 3.0 2,2-dimethyl butane -1--- 44.3 Z-m'ethyl pentane L 11.5 n-Hexane 1.1 Heptenes 2.4 Heptanes 4.5 Octenes 3.9 Octanes 9.6 Residue 6.5

The fraction consisting of six carbon atoms was 59.9 per cent of the total heavier material formed. This fraction consisted of 95 per cent of saturated hydrocarbons, of which 78 per cent was 2,2-dimethyl butane, a highly branched parafiin hydrocarbon with very good antidetonating qualities and a good component for aviation fuels. A 2,2-dimethylbutane fraction was isolated readily in a pure state by fractional distillation and had the following properties:

Blended with aviation gasoline blending stock of lower volatility, high anti-knock value and high lead responses were observed. In the pure state, the 2,2-dimethylbutane had'an anti-knock value of by the A. S. T. M. method D357-34T. This hydrocarbon is particularly suitable as an ingredient of aviation fuel and may be admixed with appropriate gasoline blending stocks, suitably in a proportion exceeding 5 per cent to impart volatility without excessive vapor pressure as well as improved anti-knock rating.

Example III Following a procedure similar to that given in Example 1, pure isobutane was used as the paraflin and pure isobutylene as the olefin component of the charge stock. In parts byweight of the hydrocarbons charged there were 10.3 parts of isobutylene and 89.7 parts of isobutane, although as a result of applying the procedure described, only a. 4 per cent concentration was maintained in the reaction zone. A pressure of 8,000 pounds per square inch and a reaction temperature of 890 F. was used, with an average reaction time of about 14.2 minutes. The products of the reaction contained 10.9 per cent by weight of hydrocarbons in the gasoline boiling range, with a possible ultimate yield based on the reper cent. The gasoline had the following composition by weight:

The fraction containing eight carbon atoms was 66.9 per cent of the total gasoline fraction and was 88 per cent branched octanes, chiefly 2,2,4-trimethylpentane and 2,5-dimethylhexane, both of high anti-knock value and lower volatility than the hexanes of Example 11.

Example IV Following the procedure as given in Example I a mixture containing in 100 parts by weight 95.2 parts of isobutane and 4.8 parts of propylene, was compressed to 4,500 pounds per square inch and acted material, by proper recyclinmof about 92 gasoline-hydrocarbon in per cent by weight was:

Per cent CsHio nu 7.7

" CuHu 3 6 CcHu 65.0

A- fraction consisting of hexanes, mostly branched, and constituting 65 per cent of the asoline was isolatedbyfraetional distillation containing 95.5 per cent hexanes associated with 4.5 per cent of hexenes, the hexanes being predominantly 3-meth'ylpentane.

Example VIII Following the procedure of Example I, isobutune and 2-butene react to form a gasoline with a. high content of branched paraflln hydrocartreated in the reaction zone at 940 F. for a period of 7.3 minutes, the fresh charge being introduced to a stream of circulating hydrocarbon; the reaction products contained 5.2 per cent of gasoline boiling range hydrocarbons by weight, which had the following analysis in parts by weight:

- Per cent C5 7.7 Ce 18.8 C1 46.7 Cu 8.6 Cu+ 12.6 Residue 5.6

The fraction containing seven carbon atoms contained 90 per cent saturated hydrocarbons from which a fraction of highly branched heptanes, with excellent antidetonating characteristics, distilling at 175 to 190 F. was separated.

Example V Following the procedure of Example I, isobutylene and methane react to yield isopentane and 2,2-dimethylpropane.

Example VI A mixture of 3.5 weight per cent of ethylene and 96.5 per cent n-butane was passed through an elongated reaction tube under a pressure of 2,600 pounds per square inch and at a temperature of 910 F. at such a rate that the reaction time was of 2.3 minutes duration. The olefin content of the mixture was low and the introduction of additional olefin to the reacting mixture not practiced, contrary to the preceding examples. The products contained 3.7 per cent by weight of gasoline hydrocarbons and per cent of the ethylene was .unreacted. The composition of the volatility and high antidetonating characteris-v tics.

Although the above detailed description shows some preferred embodiments of this invention,

the invention is not to be construed as being limited by such embodiments, and to the individual reactants described. What is claimed and desired for Letters Patent is as follows.

We claim:

1. A process for producing synthetic, predominantly branched parafilns lying within the motor fuel boiling range from para fllns and olefins'of lower molecular weight which comprises maintaining a stream of parailins of simple composition at a pressure above 1,000 pounds per square inch and a reaction temperature at which cracking proceeds only slightly, dispersing a low boiling olefin hydrocarbon material in said stream at said reaction temperature in such a manner that the concentration of unreacted olefin in the stream does not exceed 10 percent by weight, subsequently dispersing a second and different low boiling olefin hydrocarbon material in said stream at said reaction temperature in such a manner that the concentration of unreacted olefins in the stream does not exceed 10 per cent by weight, thus effecting reaction of the olefins with the paraflins to form synthetic paraflins, and then separating from the reacted mixture the synthetic paraffins so produced.

2. A process for producing synthetic, predominantly branched paraflins lying within the motor fuel-boiling range from paraifins and olefins of lower molecular weight which comprises subjecting a stream of paraflins of simple composition to a pressure in excess of 1,000 pounds per square inch and to a reaction temperature between 750 and 1100 F. for a period of time such that decomposition of paraflins does not exceed 10 per cent, dispersing a low boiling olefin hydrocarbon material in said stream during a portion of said reaction time in a manner such that the concentration of unreacted olefin does not exceed 10 per cent by weight and dispersing a second and different low boiling olefin hydrocarbon material in said stream during a subsequent portion of said reaction time in a manner such that the concentration of unreacted olefin does not exceed per cent by weight.

3. A process for producing synthetic, predominantly branched parafilns lying within the motor fuel boiling range which comprises maintaining a hydrocarbon stream composed of paraffin hydrocarbons of simple composition under a pressure in excess of 1,000 pounds per square inch at a reaction temperature between 750" and 1100" F. for a period of time such that decomposition oi paratfins does not exceed 10 per cent, dispersing a 1 reaction time at said reaction temperature and pressure at a plurality of points in an amount at each point before the last such that insufilcient free hydrogen is present to react with all of the olefinic material present and in an amount at the last point not substantially in excess of that required to react with remaining olefins, and separating iirom the resulting stream parafiins lying within the motor iuel boiling range, the entire process being conducted in the absence of a catalyst. v

4. A process for producing a synthetic, predominantly parafilnic motor fuel and controlling the volatility thereof which comprises maintaining a stream of parafilns of simple composition.

under a pressure in excess of 1,000 pounds per square inch at a reaction temperature between 750 and 1100 F. for a period of time such that decomposition of parafiins does not exceed 10 per cent, dispersing a low boiling olefin hydrocarbon material in said stream during a portion of said reaction time in a manner such that the concentration of unreacted olefin does not exceed- 10 per cent by weight, dispersing a second and different low boiling olefin hydrocarbon material in said stream during a subsequent portion of said reaction time in a manner such that the concentration of unreacted olefin does not exceed 10 per cent by weight, and controllably varying the ratio or the amount of said first olefin added to the amount of said second olefin added.

5. A process for producing synthetic, predominantly branched parafiins lying within the motor fuel boiling range from parafiins and olefins of lower molecular weight which comprises subjecting a stream of parafilns of simple composition to a pressure in excess or 1,000 pounds per square inch and to a reaction temperature between 750 to 1100 F. for a period of time such that only limited cracking takes place, dispersing a low boiling olefin of at least three carbon atoms per molecule in said stream during a portion of said reaction time in a manner such that the concentration of unreacted olefin does not exceed 10 olefin hydrocarbon material in such manner that per cent by weight, dispersing ethylene in said stream during a subsequent portion or said reaction time in a manner such that the concentration of unreacted olefin does not excee 10 per cent by weight, and finally separating from the reaction products parafiins lying within the motor fuel boiling range.

6. An improved process for the production of paramn hydrocarbons lying within themotor fuel boiling range from lower boiling 'paraflin and olefin hydrocarbons, which comprises subjecting a stream of low boiling parafiin hydrocarbons heavier than methane to alkylation conditions of temperature and pressure for a reaction time such that decomposition of paraifins does not ex-. ceed about 10 per cent, dispersing a low boiling olefin hydrocarbon material in said stream during a portion of said reaction tim in a manner such that the concentration of unreacted olefin does not exceed about 10 per cent by weight, and dispersing a second and difierent low boiling olefin hydrocarbon material in the resultant stream during a subsequent portion or said reaction time in a manner such that the concentration of unreacted olefin does not exceed about 10 per cent by weight.

'7. IA process for producing synthetic predomitended reaction zone at a pressure of at least 2,000 pounds per square inch and at a reaction temperature between 750 and 1100 F. such that less than 5 weight per cent of the parafilns undergoes decomposition for a reaction period of not over about 30 minutes and in the absence of a catalyst, introducing into an initial portion oi said reaction zone at a plurality of points 9. normally gaseous olefin hydrocarbon material in such manner that the concentration of unreacted olefin at no point exceeds 10 weight per cent or the hydrocarbons present, and introducing into a subsequent portion of said reaction zone at a plurality of points another and difierent normally gaseous the concentration of unreacted olefin at no point exceeds 10 weight per cent of the hydrocarbons present.

8. An improved process for the production of paraffin hydrocarbons lying within the motor fuel boiling range from lower-boiling parafiin and olefin hydrocarbons, which comprises subjecting a stream of low-boiling parafiln hydrocarbons heavier than methan to alkylation conditions of temperature and pressure for a reaction time such that decomposition of parafiins does not exceed about 10 per cent, dispersing. a lowboiling olefinot at least three carbon atoms per molecule in said streamduring a portion or said reaction time in a manner such that the concentration of unreacted olefin does not exceed about 10 per cent by weight, and dispersing a second and different low-boiling hydrocarbon in the resultant stream during a subsequent portion of said reaction time in a manner such that the concentration of unreacted olefin does not exceed FREDERICK E. FREY. HARDLD J.'HEPP. 

